body {
    margin: 0;
}


/* 图片主体 */
.main {
    width: 100%;
    height: 950px;
    background-color: aquamarine;
    position: relative;
}

/* 上传区域 */
.background-plate {
    width: 600px;
    height: 500px;
    background-color: antiquewhite;
    position: absolute;
    left: 50%;
    top: 40%;
    transform: translate(-50%, -50%);
    /* aspect-ratio: 16/9; 保持宽高比，宽要设成百分比，高度不用设 */
}

.layui-upload-drag {
    position: relative;
    width: 100%;
    height: 100%;
}

.center {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
}